The Science

Inspired by hemoglobin’s cooperative mechanism for binding and releasing oxygen, scientists designed new metal-organic frameworks (MOFs) that cooperatively collect and release carbon monoxide (CO) with very little energy input. Each framework has a chain of iron centers along a porous network. In these materials, CO binding at one iron site alters the electronic state of neighboring iron sites in a coordinated way. The coordination leads to the adsorption of the remaining CO along the chain in a zipper-like fashion. Similarly, with a small increase in temperature, a reversal of iron’s electronic states occurs as the CO is cooperatively released from these materials.

The Impact

The new mechanism for CO adsorption in these systems allows for significantly higher efficiencies than traditional adsorbents by combining high separation capacities with small temperature swings. These adsorbents are immediately applicable in CO separation processes such as high volume steel manufacturing and syngas production. The approach is broadly applicable to create new adsorbents for the separation of other industrially relevant gases.

Summary

Efficient adsorption-based gas separation requires maximizing both the adsorbent’s selectivity for the gas of interest and its recyclability — its easy regeneration under mild conditions. The use of communicating and responsive metal centers to enable cooperative adsorption can be used as a broader design principle for new MOFs for highly efficient separations of industrially relevant gases. Researchers at the Center for Gas Separations Relevant to Clean Energy Technologies (CGS), a DOE Energy Frontier Research Center, have now designed and demonstrated just such an efficient mechanism for CO separation in MOFs. Specifically, these materials contain a chain of interacting iron sites along the cylindrical channels where CO can adsorb. Above a threshold CO pressure, CO binding at an iron site triggers a transformation of electronic configuration more favorable for CO adsorption at neighboring iron sites, leading to a coordinated adsorption reaction. Similarly, with a small increase in temperature, a reversal of iron’s electronic states occurs as the CO molecules cooperatively desorb along the chain of iron sites in these materials. Due to this adsorption/desorption mechanism, these MOFs can exhibit large working capacities utilizing small temperature swings, making them highly energy efficient in terms of regeneration while also remaining selective for CO adsorption. Importantly, the research shows that the electronic spin transition is highly tunable through variation of the organic linkers of the framework. Hence, it is possible to design next generation materials with further improvements for CO separation from different gas mixtures. Yet another transformational aspect of this research is that a similar approach can be used to design new MOFs for the separation of a variety of other industrially relevant gases such as acetylene, ethylene, propylene, and dinitrogen.

Funding

This research was supported through the Center for Gas Separations Relevant to Clean Energy Technologies, an Energy Frontier Research Center (EFRC) funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under award DE-SC0001015. Powder X-ray diffraction data were collected at Beamline 11-BM and Beamline 17-BM at the Advanced Photon Source, a DOE Office of Science user facility, operated by Argonne National Laboratory under contract DE-AC02-06CH11357.

Filters

An international team of scientists --- including several researchers from the U.S. Department of Energy's (DOE) Argonne National Laboratory -- - has discovered an anode battery material with superfast charging and stable operation over many thousands of cycles.

Vector polarizers are a light filtering technology hidden behind the operation of many optical systems. They can be found, for instance, in sunglasses, LCD screens, microscopes, microprocessors, laser machining and more. Optical physicists published details of their new vector polarizer design this week in APL Photonics. The newly proposed design is a major advance in polarization technology because it enables flexible filtering of a wide range of light sources and generation of new light states.

Scientists have come up with a way to massively speed up the ordering process for self-assembling materials. The resulting ultra-small, well-ordered patterns could be used in the fabrication of microelectronics, antireflective surfaces, magnetic data storage systems, and fluid-flow devices.

Researchers from Stanford University, two Department of Energy national labs and the battery manufacturer Samsung created a comprehensive picture of how the same chemical processes that give cathodes their high capacity are also linked to changes in atomic structure that sap performance.

A new Petascale Data Transfer Node project aims to to achieve regular disk-to-disk, end-to-end transfer rates of one petabyte per week between major supercomputing facilities, which translates to achievable throughput rates of about 15 Gbps on real world science data sets.

Filters

NAU Regents' Professor Bruce Hungate, director of the Center for Ecosystem Science and Society (Ecoss), recently joined a new initiative lead by LLNL to study how the soil microbiome controls the mechanisms that regulate the stabilization of the organic matter in soil.

Scientists pause each afternoon at Kirtland Air Force Base in Sandia National Laboratories in Albuquerque, New Mexico, awaiting the daily lightning flash and unmistakable floor jolt that accompanies a Z shot

The University of Illinois at Chicago has received a five-year, $4.2 million grant from the U.S. Department of Energy to help industrial, commercial, institutional and utility entities evaluate and install highly efficient combined heat and power (CHP) technologies.CHP, also known as cogeneration, is a single system that produces both thermal energy and electricity.

ECS, in a continued partnership with the Toyota Research Institute of North America (TRINA), a division of Toyota Motor Engineering & Manufacturing North America, Inc. (TEMA), is requesting proposals from young professors and scholars pursuing innovative electrochemical research in green energy technology.

John Carlisle has been named the director of Chain Reaction Innovations (CRI), a program aimed at accelerating job creation through innovation, based at the U.S. Department of Energy's Argonne National Laboratory.

This fall, U.S. Department of Energy Secretary Rick Perry announced nearly $4.7 million in funding for the department's Argonne National Laboratory across 16 projects in three divisions. Four of those TCF awards, representing more than $1 million in funds, are slated for Argonne's Nuclear Engineering division.

Southern Research has been selected to receive nearly $1.7 million in U.S. Department of Energy funding to develop a new, cost-efficient gasifier capable of converting low-grade coal into synthesis gas (syngas) that can be used in a number of applications.

The world's most advanced particle accelerator for investigating the quark structure of matter is gearing up to begin its first experiments following official completion of an upgrade to triple its original design energy. The Continuous Electron Beam Accelerator Facility (CEBAF) at the Department of Energy's Thomas Jefferson National Accelerator Facility is now back online and ramping up for the start of experiments.